Stratigraphy, palaeomagnetism and age of volcanics in the upper regions of ÞJórsárdalur valley, central southern Iceland

• Published in: Boreas
• Main Authors: KRISTJÁNSSON, LEÓ, DUNCAN, ROBERT A., GUÐMUNDSSON, ÁGÚST
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1998
• Subjects: Þjórsárdalur; Hreppar; Iceland
• Online Access: http://dx.doi.org/10.1111/j.1502-3885.1998.tb00863.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1998.tb00863.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1998.tb00863.x

The ‘Hreppar Formation’ of southern Iceland is a succession mostly composed of basalt lavas and clastic material, with a slight anticlinal structure. It may represent a crustal fragment left in place by eastwards movement of the active spreading zone during the past 2–3 Ma. Evidence of several cycles of alternating glacial‐interglacial conditions is seen in this succession. The first systematic stratigraphic study within the succession which is combined with K‐Ar age determinations and laboratory palaeomagnetic measurements on oriented cores has yielded encouraging results. The age determinations confirm earlier estimates by Icelandic geologists on the age range spanned by the Hreppar succession. Units from the Jaramillo geomagnetic subchron are present in its upper part, and at least one polarity reversal event in the lower Matuyama chron is also recorded.